Place the chicken, butter, soup and onion in a slow cooker. Pour broth into crock pot to cover chicken. If additional liquid needed, add enough water to cover. Cook for 5 to 6 hours on high. Shred chicken. About 1 hour before serving, place the sliced biscuit dough in the slow cooker, making sure biscuits are submerged in chicken mixture. Cook until the dough is no longer raw in center.